1. Field of the Invention
This invention relates to surgical instruments and, more particularly, to instruments for applying surgical closure devices such as ligating clips and staples. Still more particularly, the invention relates to automatic surgical clip appliers and the means by which individual ligating clips are advanced to the clip-closing jaws at the distal end of the instrument.
2. Description of the Prior Art
Surgical ligating or hemostatic clips are used to ligate blood vessels, ducts or other tissue during surgery. The terms "ligating" and "hemostatic" are used interchangeably herein and, since these devices generally bind an object they will occasionally be termed "binding devices". The clips are generally U-shaped, have two parallel legs joined by an integral hinge portion and are applied with a clip applying forceps-type instrument used to crimp the clip legs together about the tissue to be ligated. When first introduced many years ago, each clip had to be applied individually by placing it in the jaws of a so-called "manual" clip applying, forceps-type instrument, and squeezing the jaws together. The clips for use with manual appliers are stored in a separate clip cartridge or dispenser from which the clips are retrieved one at a time. While manual appliers are still used, subsequent instruments were "automatic" clip appliers (some of them disposable) and incorporated a clip dispenser as part of the clip applying instrument. These improvements in clip appliers made these devices automatic in the sense of being able to automatically feed clips sequentially into the jaws. The automatic instruments generally include a pair of jaws for receiving, holding and crimping a single clip at a time and a feeding means for feeding a clip from the dispenser to the jaws. The jaws and feeder are activated in proper sequence by an activating means which usually includes a pistol-grip or pair of handles coupled mechanically to the feeder and jaws. The sequencing cycle may be done in a variety of ways but, generally, after the jaws are closed to crimp one clip the jaws are opened and supplied with a new clip ready to be applied when the jaws are closed again. Since different surgical procedures require the use of varying numbers of ligating clips, the automatic appliers are pre-loaded with different numbers of clips and in varying sizes. See, for example, U.S. Pat. No. 4,712,549 (Peters et al.), assigned to the assignee of this invention. While beneficial in many respects, the automatic appliers detract from the "feel" of manual appliers.
The simplicity of manual surgical clip appliers enables them to provide the surgeon with immediate tactile feedback because the "feel" of the clip being applied to the vessel is immediately transmitted from the distal, jaw end of the clip applier to the proximal, handle end. There is a direct connection between the two ends and any motion (i.e. squeezing) of the handle which is immediately transmitted to a corresponding motion of the jaws.
Automatic appliers, however, have always used a portion of the jaw closing mechanism to actually feed or move the clip from its storage cartridge or dispenser to the jaws. Sometimes, this is done by having the handles compress a spring during one portion of the cycle, the energy of the spring then being used in another portion of the cycle to feed a clip. In other instances, the handles move a feeder member in one portion of the cycle to push a clip into the jaws. The extra handle motion required to feed a clip rather than crimp it makes automatic appliers feel different to the user.
With the recent interest in endoscopic surgical procedures, surgical clip appliers have been adapted for endoscopic use by, among other things, somewhat disassociating clip-feeding from clip-crimping. This enhances security by enabling a surgeon during an endoscopic procedure to insert a clip applier into a cannula and place a clip between the jaws only when desired. Thus, in some prior art automatic clip appliers, the means by which a clip is fed to the jaws is independently triggered by actuation of a trigger mechanism while separate actuation of a jaw closing mechanism (for example, by squeezing a handle) actually closes the clip. However, even in these devices the movement of the jaw closing mechanism is linked to the clip feeding mechanism so that the user still does not get a true "feel" when the jaws are closed.
For example, U.S. Pat. No. 5,084,057 (Green et al.) discloses an apparatus and method for applying surgical clips in laparoscopic or endoscopic procedures. The device has a pistol grip actuating mechanism for closing the jaws and feeding the clip to the jaws. While the clip advancing mechanism is prepared for feeding a clip to the jaws, the actual feeding of the clip is interrupted by a trigger interposed between the feeding mechanism and the actuating mechanism so that clips will only be fed when the trigger is activated--not automatically as in other automatic clip appliers.
Another instrument which separates clip-feeding from clip-crimping is disclosed in U.S. Pat. No. 5,112,343 (Thornton), assigned to the assignee hereof. This applier has pair of handles which are squeezed to compress a spring which is then released by a trigger to feed the clip. The releasing mechanism includes a trigger to move a resilient pawl out of engagement with a locking surface.
U.S. Pat. No. 4,662,373 (Montgomery et al.) discloses another example in the form of a surgical ligating instrument having a first activating means (e.g. a trigger) for activating a clip injector to push a clip into the jaws and a second activating means (e.g. a handle) for closing the jaws to crimp the clip. While first and second activating means are primarily independent they are interconnected mechanically such that actuation of the handle to crimp the clip does move other components in order to enable the clip injecting mechanism to be reset. The very nature of this interaction between the first and second activating mechanisms is sufficient to compromise the "feel" of the handle actuating mechanism.
It is an object of this invention to produce an automatic surgical clip applier which approximates the "feel" of a manual clip applier.
It is yet another object of this invention to produce an automatic surgical clip applier having one actuating mechanism for feeding the clip into the jaws of the applier and a second actuating mechanism for closing the jaws, the first and second actuating mechanisms being substantially mechanically independent of each other. It is another object of this invention to produce an automatic surgical clip applier wherein the means by which a clip is fed into the jaws of the applier works with a substantially constant feeding force with respect to each clip stored in the applier.
An additional object of this invention is to produce a surgical clip applier having a stored energy mechanism that is preloaded with and stores enough energy to feed all the clips in the entire cartridge.
It is yet another object of this invention to produce a surgical instrument having a self-contained energy source which can be used to physically move a desired component of the instrument.
It is also an object of this invention to provide a clip applier having a self-contained power source for feeding clips to the applier jaws which source is located along with the clips at the distal tip of the instrument. This arrangement facilitates simplification of the proximal handle end of the instrument and is adaptable to an instrument having a reusable handle end and a disposable or interchangeable distal tip containing the clips, jaws and power source.